Micro-Electro-Mechanical System (MEMS) technology is a fast growing technology. In the MEMS technology, micro/nano sized materials/structures are designed, fabricated, measured, and controlled to be functional devices. Currently, MEMS devices in the market include acceleration sensors and pressure sensors.
The MEMS acceleration sensors are devices utilizing the inertia property to perform the measurement. Based on sensing principles, the MEMS acceleration sensors can be categorized into different groups, including piezoresistive type, capacitive type, piezoelectric type, tunneling current type, resonant type, thermoelectric type, electromagnetic coupling type, etc. The MEMS acceleration sensors are widely used in the field of consumer electronics such as cell phones, game consoles, and other portable devices. The MEMS acceleration sensors are also widely used in the field of automotive industry, e.g., in the electronic stability control (ESC) and/or the electronic stability program (ESP), such as in the automotive airbags, the vehicle attitude measurements, and the GPS-aided navigation systems. Further, the MEMS acceleration sensors are also used in the fields of military and aerospace, such as in the satellite wireless communications and the missile guidance.
The MEMS pressure sensors are devices used to measure the pressure. Current MEMS pressure sensors include the silicon piezoresistive pressure sensor and the silicon capacitive pressure sensor. The silicon piezoresistive pressure sensor and the silicon capacitive pressure sensor are MEMS sensors formed on the silicon substrates. The MEMS pressure sensors are widely used in automotive electronics such as the tire pressure monitoring systems (TPMS); in consumer electronics such as the tire pressure meters and the sphygmomanometers; in industrial electronics such as the digital pressure meters, the digital flow meters and the industrial supply weightings, etc.
A MEMS pressure sensor usually includes a semiconductor substrate; a bottom electrode located on the semiconductor substrate; a sensing film located above the bottom electrode; a gap formed between the sensing film and the bottom electrode; and supporting structures located on the semiconductor substrate used for supporting the sensing film.
As illustrated above, MEMS sensors are widely used in consumer electronics, automotive electronics, and industrial electronics. However, because of great differences between various sensors in fabrication and packaging, to the date, there are no integrated MEMS sensor products on the market.
For example, although the MEMS acceleration sensors and the MEMS pressure sensors are already used in the TPMS, chips of the MEMS acceleration sensors and the MEMS pressure sensors are first designed and fabricated separately, and then packaged together. Consequently, existing MEMS devices having integrated multiple MEMS sensors may have complicated fabrication process and may be large in the volume with high cost. The disclosed devices and methods are directed to solve one or more problems set forth above and other problems.